Polyploidization of Ngoc Linh Ginseng (Panax vietnamensis Ha et Grushv.) by colchicine treatment

Polyploidization is a crucial pathway for enhancing the medicinal contents in herb plants, particularly in Ngoc Linh ginseng (Panax vietnamensis Ha et Grushv.), a rare and endemic medicinal plant of Vietnam. Chromosome duplication can lead to changes in genetic material that encode or are linked to desired traits. This study aimed to develop tetraploid Ngoc Linh ginseng from somatic embryos using colchicine treatment. Globular embryos were soaked in colchicine solutions ranging from 0.025% to 0.4% for exposure times between 24 and 72 hours. The polyploidy level of Ngoc Linh ginseng was screened using flow cytometry and confirmed by chromosome counting at the root tip. The tetraploid ginseng leaves identified after screening were then utilized to regenerate euploid plants. Results indicated that a colchicine concentration of 0.1% with a 72-hour exposure was optimal for inducing polyploid in Ngoc Linh ginseng embryos. Furthermore, three regenerated eu-tetraploid ginseng plants displayed no chimerism and exhibited increased phenotypic traits, including thicker leaves, taller shoots, and longer leaves, compared to the diploid variety. The successful regeneration of eu-tetraploid Ngoc Linh ginseng, with observable phenotypic changes, holds promising potential for production applications.